[PATCH v3 09/10] gpu: nova-core: Add self-test assertion macros and config option

[Eliot Courtney <ecourtney@nvidia.com>]

The existing assert! and assert_eq! macros cause a panic. For self tests
in nova-core, it's inconvenient to cause a panic since these need to be
run on actual hardware. Instead, define similar macros that log an error
then return an Err.

Also add the NOVA_CORE_SELFTESTS Kconfig option that gates the driver
self-tests.

Signed-off-by: Eliot Courtney <ecourtney@nvidia.com>
---
 drivers/gpu/nova-core/Kconfig      |  9 ++++++
 drivers/gpu/nova-core/nova_core.rs |  2 ++
 drivers/gpu/nova-core/selftest.rs  | 64 ++++++++++++++++++++++++++++++++++++++
 3 files changed, 75 insertions(+)

diff --git a/drivers/gpu/nova-core/Kconfig b/drivers/gpu/nova-core/Kconfig
index f918f69e0599..cb7f0b00f796 100644
--- a/drivers/gpu/nova-core/Kconfig
+++ b/drivers/gpu/nova-core/Kconfig
@@ -15,3 +15,12 @@ config NOVA_CORE
 	  This driver is work in progress and may not be functional.
 
 	  If M is selected, the module will be called nova-core.
+
+config NOVA_CORE_SELFTESTS
+	bool "Nova Core driver self-tests"
+	depends on NOVA_CORE
+	default n
+	help
+	  Build the driver self-tests and run them when the GPU is probed.
+
+	  If unsure, say N.
diff --git a/drivers/gpu/nova-core/nova_core.rs b/drivers/gpu/nova-core/nova_core.rs
index 8f59cfa97017..1133c6ce5c55 100644
--- a/drivers/gpu/nova-core/nova_core.rs
+++ b/drivers/gpu/nova-core/nova_core.rs
@@ -23,6 +23,8 @@
 mod num;
 mod regs;
 mod sbuffer;
+#[cfg(CONFIG_NOVA_CORE_SELFTESTS)]
+mod selftest;
 mod vbios;
 mod vgpu;
 
diff --git a/drivers/gpu/nova-core/selftest.rs b/drivers/gpu/nova-core/selftest.rs
new file mode 100644
index 000000000000..f5b5965b7e6a
--- /dev/null
+++ b/drivers/gpu/nova-core/selftest.rs
@@ -0,0 +1,64 @@
+// SPDX-License-Identifier: GPL-2.0
+// SPDX-FileCopyrightText: Copyright (c) 2026 NVIDIA CORPORATION & AFFILIATES. All rights reserved.
+
+//! Assertion macros for driver self-tests.
+//!
+//! Self-tests run against live hardware during probe, so a failed assertion should not panic. These
+//! macros log the failure on the device and fail the enclosing test by returning
+//! [`EIO`](kernel::error::code::EIO) instead.
+
+/// Like [`assert!`], but logs the failure via `dev` and fails the enclosing test instead of
+/// panicking.
+///
+/// As with [`assert!`], a custom message with format arguments can follow the condition.
+#[macro_export]
+macro_rules! selftest_assert {
+    ($dev:expr, $cond:expr $(,)?) => {
+        $crate::selftest_assert!($dev, $cond, "assertion failed: {}", ::core::stringify!($cond))
+    };
+    ($dev:expr, $cond:expr, $($arg:tt)+) => {{
+        if !$cond {
+            ::kernel::dev_err!(
+                $dev,
+                "Selftest: {}:{}: {}\n",
+                ::core::file!(),
+                ::core::line!(),
+                ::kernel::prelude::fmt!($($arg)+)
+            );
+            return Err(::kernel::error::code::EIO);
+        }
+    }};
+}
+
+/// Like [`assert_eq!`], but logs the failure via `dev` and fails the enclosing test instead of
+/// panicking.
+///
+/// As with [`assert_eq!`], a custom message with format arguments can follow the compared values.
+#[macro_export]
+macro_rules! selftest_assert_eq {
+    ($dev:expr, $left:expr, $right:expr $(,)?) => {
+        match (&$left, &$right) {
+            (left, right) => $crate::selftest_assert!(
+                $dev,
+                left == right,
+                "assertion `{} == {}` failed: left {:?}, right {:?}",
+                ::core::stringify!($left),
+                ::core::stringify!($right),
+                left,
+                right
+            ),
+        }
+    };
+    ($dev:expr, $left:expr, $right:expr, $($arg:tt)+) => {
+        match (&$left, &$right) {
+            (left, right) => $crate::selftest_assert!(
+                $dev,
+                left == right,
+                "assertion `left == right` failed: {}: left {:?}, right {:?}",
+                ::kernel::prelude::fmt!($($arg)+),
+                left,
+                right
+            ),
+        }
+    };
+}

-- 
2.55.0